It's been nearly 25 years since the UFC held its first event on Nov. 12, 1993, inside Denver's McNichols Sports Arena.

The sport of mixed martial arts, not to mention the business and regulation practices surrounding it, have evolved to a point its barely recognizable with that inaugural event.

And virtually none of the original cast of characters who created and competed in UFC 1 are still affiliated with the promotion today.

Royce Gracie, right, defeated Gerard Gordeau, left in the final of UFC 1 in 1993. Holly Stein/Getty Images

A Tuesday release of ESPN's 30-for-30 podcast series tells the story of UFC 1 unlike it's ever been told before. The episode features first-hand accounts of a last-minute rules meeting that nearly derailed the entire event, a staff member struggling to cope with the violence of the early bouts, and even a near-death experience.

ESPN spoke to producer Chris Berube, of Pineapple Street Media, about his experience working on the 30-for-30 project.

How did you become involved in this story?

I knew ESPN was bringing us on to do a 30-for-30 episode. I think about two or three days before my first reporting trip is when they told us it was about the UFC. I'm a pretty casual fan of the UFC. My dad really got me into the UFC around the time Dana White became the face of it. But for me, I didn't know this whole back story or the history behind it.

For many fans, there's kind of this vague sense of what the old days used to be like, but there's this complicated story with a lot of good characters that a lot of people just don't know about.

You managed to track down a lot of the people involved with UFC 1, including the fighters. How challenging was that?

Some guys were really easy. Some were really hard. I think some of them want to remind people of their place in the history of the UFC. For others, it's painful they're not involved anymore. Some of them have simply done a lot of different things over the last 25 years and they don't really want to talk about something so far in their past.

Royce Gracie, bottom, submitted Ken Shamrock in less than a minute in the semifinals of UFC 1 in 1993. Holly Stein/Getty Images

One thing I found interesting is that, for the fighters, it's still very present. Ken Shamrock can talk about this like it happened yesterday. He still vividly remembers the emotions of going through the first surprising loss of his career, to Royce Gracie.

When you say it's painful for some, is that because of how big the UFC has become since those early days?

You know, enough time has passed that a lot of people seem to be at peace with that. The organizers -- Rorion Gracie, Art Davie, Campbell McLaren, Bob Meyrowitz -- what all of them kind of expressed is they personally could not have made it into a $4 billion company. Meyrowitz lost millions, for years, to keep it going. Then the Fertitta brothers who bought it had to sink tens of millions more, with no guarantee that money was ever coming back.

Even though it's become this pop cultural phenomenon, none of those guys knew back then if it was going to survive. So, I think they've come to terms with it in that way.

Did you get a sense if the fighters, besides Royce Gracie, ever wonder what would have happened if they'd won?

For sure. One question that kept coming up was what the UFC would have been like if Royce had lost. It's impossible to answer that obviously, but I think most agree that Royce winning and setting up a rivalry with Ken Shamrock really helped the UFC.

For the UFC to set up an iconic rivalry right away, with two physically different guys with different attitudes -- you know, a lot of people told me they thought the boxer was going to win. The biggest, hardest-hitting guy, that just sounded logical. And if that had happened, I don't know what would have happened to the UFC. I don't know what would have happened if a savate fighter from Holland had won. I don't know what would have happened if the Gracie family hadn't been able to prove the point they were trying to, about a smaller fighter beating a bigger fighter.

Is there anyone you really wanted to talk to that you weren't able to?

One person was Dana White. We were supposed to get him around the time of the shooting in Las Vegas and that trip didn't end up happening. I feel really glad though, that we were able to speak to a lot of the people who where there at the very beginning. [Fighter] Kevin Rosier died a year or two ago. Another one we didn't get was Pat Smith. But we did about 40 hours of interviews, way more material than we could have ever used.

How close UFC 1 come to not even happening?

It depends who you ask. There are a lot of lucky breaks in this story, and there were many moments where it could have fallen apart. Something a lot of people focus on is a fighter meeting, where they were all supposed to sign a waiver. There weren't many rules at UFC 1 but there were some, and a lot of those were rules the organizers didn't think would be controversial that ended up being very controversial.

I think the more interesting question is: How close did it come to never happening again? The first fight in the UFC was 26 seconds long. If all the fights had been that long, it wouldn't have been a full feature-length broadcast and people probably would have hated it. They god lucky the other fights went the way they did.

Is there anything you had to cut from the final version for the sake of time you wish you could have included?

Lots of stuff. I really sincerely hope we've done justice to the people involved. There are just such a wide cast, we weren't able to include everyone, which I regret. Like, Jim Brown was one of the commentators that night, and he doesn't even come up in the documentary. Why was football legend Jim Brown on commentary at UFC 1? No one really knew. McLaren said, 'Well, we thought it would be cool,' but no one really had an explanation as to why it was cool or a good idea.

There were behind the scenes stuff like that I wish we could have gotten into, but unfortunately we had a limited amount of time. I hope a longer piece about the UFC earlier days gets made some day. It was such a chaotic time, there's a rich history there.